Expansion valve performance monitoring in refrigeration system

ABSTRACT

A method of detecting electrical failure in a refrigeration system is provided. The method includes determining whether a present superheat of the refrigeration system is between a maximum superheat and a minimum superheat for the refrigeration system, the maximum superheat and the minimum superheat defining a normal operating range. The method also includes detecting an electrical property of an expansion valve assembly of the refrigeration system responsive to the superheat being outside the normal operating range. The method further includes determining whether the expansion valve assembly as experienced an electrical failure based on at least the electrical property. A signal indicating that the expansion valve has experienced an electrical failure is generated based on a determination that the expansion valve assembly has experienced the electrical failure.

BACKGROUND

The present disclosure relates generally to the field of refrigerationsystems, including for refrigerated display cases. More specifically,the present disclosure relates to the field of controllers anddiagnostic systems for refrigeration systems.

SUMMARY

At least one embodiment of the present disclosure relates a method ofdetecting electrical failure in a refrigeration system. The methodincludes determining whether a present superheat of the refrigerationsystem is between a maximum superheat and a minimum superheat for therefrigeration system. The maximum superheat and the minimum superheatdefine a normal operating range. The method also includes detecting anelectrical property of an expansion valve assembly of the refrigerationsystem in response to the superheat of the refrigeration system beingoutside of the normal operating range, determining whether the expansionvalve assembly has experienced an electrical failure based on at leastthe electrical property of the expansion valve assembly, and generatinga first signal indicating that the expansion valve assembly hasexperienced the electrical failure in response to a determination thatthe expansion valve assembly has experienced the electrical failure.

Another embodiment of the present disclosure relates to a system (e.g.,a refrigeration system). The system includes a housing defining atemperature controlled space and a thermal exchange system, coupled tothe housing. The thermal exchange system is configured to selectivelycontrol a temperature of the temperature controlled space. The thermalexchange system includes an actuator and a controller. The controller isconfigured to determine whether a present superheat of the refrigerationsystem is between a maximum superheat and a minimum superheat for therefrigeration system. The maximum superheat and the minimum superheatdefine a normal operating range. The controller is also configured todetect an electrical property of an expansion valve assembly of therefrigeration system in response to the superheat of the refrigerationsystem being outside of the normal operating range, determine whetherthe expansion valve assembly has experienced an electrical failure basedon at least the electrical property of the expansion valve assembly, andgenerate a first signal indicating that the expansion valve assembly hasexperienced the electrical failure in response to a determination thatthe expansion valve assembly has experienced the electrical failure.

Another embodiment of the present disclosure relates to a controller fordiagnosing a refrigeration system. The controller configured todetermine a present superheat of the refrigeration system and a maximumsuperheat and a minimum superheat for the refrigeration system. Themaximum superheat and the minimum superheat define a normal operatingrange. The controller is also configured to detect, an electricalproperty of an expansion valve assembly of the refrigeration systemresponsive to the present superheat of the refrigeration system beingoutside of the normal operating range, determine whether the expansionvalve assembly has experienced an electrical failure based on at leastthe electrical property of the expansion valve assembly, and generate afirst signal indicating that the expansion valve assembly hasexperienced the electrical failure responsive to a determination thatthe expansion valve assembly has experienced the electrical failure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a refrigerated display case according toan exemplary embodiment.

FIG. 2 is a block diagram of a refrigeration system and associatedcomponents, according to an exemplary embodiment.

FIG. 3 is a detailed block diagram of the refrigeration system of FIG.2, according to an exemplary embodiment.

FIG. 4 is a detailed block diagram of the refrigeration system of FIG.2, according to an exemplary embodiment.

FIG. 5 is a block diagram of a controller for the refrigeration systemof FIG. 2 and associated components, according to an exemplaryembodiment.

FIG. 6 is a flowchart of a process for monitoring and diagnosing anexpansion valve of the refrigeration system of FIG. 2, according to anexemplary embodiment.

FIG. 7 is a flowchart of a process for failure mitigation controls ofthe refrigeration system of FIG. 2, according to an exemplaryembodiment.

FIG. 8 is a chart of current vs time measured within the refrigerationsystem of FIG. 2, according to an exemplary embodiment.

FIG. 9 is a chart of current vs time measured within the refrigerationsystem of FIG. 2, according to an exemplary embodiment.

DETAILED DESCRIPTION

Referring generally to the FIGURES, a refrigeration system andcomponents thereof are shown, according to various exemplaryembodiments. The refrigeration system may be a vapor compressionrefrigeration system. In some implementations, the refrigeration systemmay be used to provide cooling for temperature-controlled displaydevices in a supermarket or other similar facility.

In some embodiments, the refrigeration system includes a receiving tank(e.g., a flash tank, a refrigerant reservoir, etc.) containingrefrigerant, a condenser assembly, a compressor assembly, anaccumulator, a subcooler assembly, and a superheater assembly. Therefrigeration system includes a controller for monitoring andcontrolling the pressure, temperature, and/or flow of the refrigerantthroughout the refrigeration system. The controller can operate each ofthe assemblies (e.g., according to the various control processesdescribed herein) to efficiently regulate the pressure of therefrigerant within the receiving tank. Additionally, the controller caninterface with other instrumentation associated with the refrigerationsystem (e.g., measurement devices, timing devices, pressure sensors,temperature sensors, etc.) and provide appropriate control signals to avariety of operable components of the refrigeration system (e.g.,compressors, valves, power supplies, flow diverters, etc.) to regulatethe pressure, temperature, and/or flow at other locations within therefrigeration system. Advantageously, the controller may be used tofacilitate efficient operation of the refrigeration system, reduceenergy consumption, improve system performance, and diagnose problemswithin the system.

Before discussing further details of the refrigeration system and/or thecomponents thereof, it should be noted that references to “front,”“back,” “rear,” “upward,” “downward,” “inner,” “outer,” “right,” and“left” in this description are merely used to identify the variouselements as they are oriented in the FIGURES. These terms are not meantto limit the element which they describe, as the various elements may beoriented differently in various applications.

It should further be noted that for purposes of this disclosure, theterm “coupled” means the joining of two members directly or indirectlyto one another. Such joining may be stationary in nature or moveable innature and/or such joining may allow for the flow of fluids,transmission of forces, electrical signals, or other types of signals orcommunication between the two members. Such joining may be achieved withthe two members or the two members and any additional intermediatemembers being integrally formed as a single unitary body with oneanother or with the two members or the two members and any additionalintermediate members being attached to one another. Such joining may bepermanent in nature or alternatively may be removable or releasable innature.

Referring now to FIG. 1, a perspective view of a refrigerated displaycase 100 is shown, according to an exemplary embodiment. Therefrigerated display case 100 includes a refrigeration body 101 whichdefines a temperature controlled space 103. The refrigerated displaycase 100 may include a mechanical-compression refrigeration system, anabsorption refrigerating system, an evaporative cooling system, or athermoelectric refrigeration system configured to selectively control atemperature of the temperature controlled space 103. In someembodiments, the refrigerated display case 100 may be a standalone unit.In other embodiments, the refrigerated display case 100 may be part of alarger refrigeration system.

Referring now to FIG. 2, a block diagram of a refrigeration system 105is shown, according to an exemplary embodiment. The refrigeration system105 is coupled to and configured to selectively control the temperatureof the temperature controlled space 103. The refrigeration system 105includes a refrigerant disposed therein. The refrigerant is configuredto facilitate thermal energy exchange throughout the refrigerationsystem 105. The refrigeration system 105 also includes a condenserassembly 110 configured to facilitate thermal energy loss from therefrigerant. The condenser assembly 110 includes a fan 115 configured toassist in the thermal energy loss. The condenser assembly 110 is fluidlycoupled to an expansion valve assembly 120 by liquid line 117.

The expansion valve assembly 120 is configured to facilitate a pressuredrop in the refrigerant. During the pressure drop, the refrigerantchanges phase from a liquid to a vapor. The expansion valve assembly 120is fluidly coupled to an evaporator assembly (e.g., a coil, etc.) 150 byfluid line 127. Fluid line 127 includes an inlet sensor 310. The inletsensor 310 is configured to measure the temperature or the pressure ofthe refrigerant. In other embodiments, the inlet sensor 310 is part ofthe expansion valve assembly.

The evaporator assembly 150 is coupled to the temperature controlledspace 103. The evaporator assembly 150 is configured to facilitatethermal energy gain in the refrigerant. The evaporator assembly 150includes a fan 155 configured to assist in the thermal energy gain. Theevaporator assembly 150 is fluidly coupled to a compressor assembly 160by vapor line 157. Vapor line 157 includes outlet sensor 320. The outletsensor 320 is configured to measure the temperature or the pressure ofthe refrigerant. The compressor assembly 160 is configured to increasethe pressure of the refrigerant. The compressor assembly is fluidlycoupled to the condenser assembly 110 by a discharge line 167.

The refrigeration system 105 also includes a power supply 190 and acontroller 200. The controller 200 is configured to send and receivecontrol signals to each of the components of the refrigeration system105. As shown the controller is coupled to (1) the fan 115 by controlline (e.g., conductive path, wire, cable, etc.) 307, (2) the inletsensor 310 by control line 317, (3) the outlet sensor 320 by controlline 327, (4) the fan 155 by control line 357, (4) the compressorassembly 160 by control line 367, and (5) the expansion valve assembly120 by control line 397. In additional exemplary embodiments, thecontroller 200 may be coupled to each of the components of therefrigeration system 105 such that the controller can send and receivesignals from each of the components of the refrigeration system 105.Furthermore, the control lines may be configured to facilitate theexchange of data, signals (e.g., analog or digital), power, etc.

In some embodiments, the controller is also configured to facilitatepower delivery to each of the components of the refrigeration system105. In the embedment shown in FIG. 2, the power supply 190 is directlyelectrically coupled to the controller by power line 195 and indirectlycoupled to each of the other components of the refrigeration system 105via the controller. In a different embodiment, the power supply 190 maybe directly electrically coupled to each of the components of therefrigeration system 105. In this embedment, the controller may controlthe power supply 190 to selectively provide power to each of thecomponents of the refrigeration system 105.

In other exemplary embodiments, the refrigeration system 105 may beconfigured as a thermal exchange system (e.g., refrigeration system, airconditioning system, heat pump, etc.) configured to facilitate thermalenergy exchange. In these embodiments, the system may include the sameor similar components, assemblies, and control logic as therefrigeration system 105.

Now referring to FIG. 3, a detailed view of the block diagram of FIG. 2is shown, according to an exemplary embodiment. The controller 200 isshown as coupled to the expansion valve assembly 120 by control line397. The expansion valve assembly 120 is shown as including an expansionvalve 121 and an actuator 125 (e.g., pneumatic actuator, hydraulicactuator, D/C motor, A/C motor, etc.). The actuator 125 is configured toreceive a control signal from controller 200 via the control line 397and actuate the expansion valve 121.

In some embodiments, the actuator 125 may be configured as a D/C motor.More specifically, the actuator 125 may be configured as a steppermotor. In this configuration, the actuator 125 selectively actuates theexpansion valve 121 in a plurality of positions. A first position may bea fully open position. A second position may be a fully closed position.Other positions may be disposed between the first position and thesecond position.

An actuator sensor 325 is coupled to the actuator 125 by control line324, as shown. The actuator sensor 325 is configured to continuallycollect data about the actuator 125. The actuator sensor 325 is furtherconfigured to send the collected data to the controller by control line326.

In other embodiments, the actuator sensor 325 may be integrated with theactuator 125 such that the actuator sensor 325 and the actuator 125 area single unit. Additionally, the control line 324 and control line 326may be integrated with control line 397. In one exemplary embodiment,the actuator sensor 325 may be configured to detect an electrical eventat (e.g., within, along a path entering or exiting) the expansion valveassembly 120. For example, the sensor may be configured to detect avoltage, a current, a power, or other electrical property (e.g., voltagespike, current spike, power spike, etc.) of the expansion valve assembly120. In another exemplary embodiment, the actuator sensor 325 isconfigured as an encoder configured to measure the displacement of theactuator 125.

The expansion valve assembly 120 is fluidly coupled to the evaporatorassembly 150 by fluid line 127. The fluid line 127 includes an inletsensor 310 (see FIG. 2). The inlet sensor 310 includes an inlettemperature sensor 311 and an inlet pressure sensor 312 as shown in FIG.3. The inlet temperature sensor 311 and the inlet pressure sensor 312are coupled to the fluid line 127 by control line 317. The inlettemperature sensor 311 is configured to continuously collect data aboutthe temperature of the refrigerant at the fluid line 127 and send thedata to the controller 200. The inlet pressure sensor 312 is configuredto continuously collect data about the pressure of the refrigerant atthe fluid line 127 and send the data to the controller 200 by controlline 317. In other embodiments, the inlet temperature sensor 311 and theinlet pressure sensor 312 are integrated into the expansion valveassembly 120. In a different embodiment, the inlet temperature sensor311 and the inlet pressure sensor 312 are coupled directly to the fluidline 127.

The evaporator assembly 150 is fluidly coupled to the compressorassembly 160 (see FIG. 2) by vapor line 157. The vapor line 157 includesan outlet sensor 320 (see FIG. 2). The outlet sensor 320 includes anoutlet temperature sensor 321 and an outlet pressure sensor 322 as shownin FIG. 3. The outlet temperature sensor 321 and the inlet pressuresensor 312 are coupled to the vapor line 157 by control line 327. Theoutlet temperature sensor 321 is configured to continuously collect dataabout the temperature of the refrigerant at the vapor line 157 and sendthe data to the controller 200. The outlet pressure sensor 322 isconfigured to continuously collect data about the pressure of therefrigerant at the vapor line 157 and send the data to the controller200 by control line 327. In a different embodiment, the inlettemperature sensor 311 and the inlet pressure sensor 312 are coupleddirectly to the vapor line 157.

The controller 200 is configured to receive data from the actuatorsensor 325, the inlet temperature sensor 311, the inlet pressure sensor312, the outlet temperature sensor 321, and the outlet pressure sensor322. The controller 200 is further configured to send a control signalto the actuator 125 based on the data received from the actuator sensor325, the inlet temperature sensor 311, the inlet pressure sensor 312,the outlet temperature sensor 321, and the outlet pressure sensor 322.

Now referring to FIG. 4, a block diagram of another exemplary embodimentof the refrigeration system 105 of FIG. 2 is shown. The embodiment shownin FIG. 4 includes an ambient temperature sensor 361 and an ambientpressure sensor 362 coupled to the controller 200 by control line 367.Ambient temperature sensor 361 is configured to measure ambienttemperature (i.e. the temperature outside of the temperature controlledspace 103 or the refrigerated display case 100). Ambient pressure sensor362 is configured to measure ambient pressure (i.e. the pressure outsideof the temperature controlled space 103 or the refrigerated display case100).

In additional exemplary embodiments, the refrigeration system 105 mayonly include some of the temperature sensors or the pressure sensorsshown in the embodiments of FIGS. 2-4. For example, the refrigerationsystem 105 may only include pressure sensors. Alternatively, therefrigeration system 105 may include any combination of temperature andpressure sensors. In these embodiments, the controller may be configuredto determine a temperature based on the type of refrigerant and thepressure measured from a pressure sensor. Alternatively, the controllermay be configured to determine a pressure based on the type ofrefrigerant and the temperature measured from a temperature sensor.Various combinations of sensors are within the scope of the presentdisclosure.

Now referring to FIG. 5, a block diagram of the controller 200 is shown,according to an exemplary embodiment. The controller 200 includes aprocessing circuit 400. The processing circuit 400 includes a processor405 and a memory device 410. The processing circuit is communicablycoupled (e.g., conductively linked) to various interfaces on thecontroller 200. The processing circuit is configured to receive andtransmit data from the interfaces on the controller 200.

The controller 200 is shown as including a user interface 420. The userinterface 420 includes a signaling device 425. The user interface 420 isconfigured to receive or provide signals from/to a control panelprovided with the display case. The control panel may include digital oranalog input/output devices for example a display (e.g., LCD, OLED,etc.), an audio device (e.g., speaker, etc.), or an indication device(e.g., LED, etc.) configured to present the data to the user. Forexample the user interface 420 may be configured to receive data from auser input such as ambient pressure, ambient temperature, desiredsuperheat or subcooling conditions, or other parameters relevant to theoperation of the refrigeration system 105 (see FIG. 2). Additionally,the user interface 420 may be configured to provide information to theuser such as data collected by various sensors of the refrigerationsystem 105. The user interface 420 includes a signaling device 425configured to provide a signal to the control panel. For example, thesignaling device 425 may be configured to present operational data aboutthe refrigeration system 105. The signaling device 425 may be configuredto notify the user that the refrigeration system 105 is operating withinthe specified parameters, or that the refrigeration system 105 hasexperienced a failure to one or more components. For example, thesignaling device 425 may light up an LED indication light if certainconditions are meet. More specifically, the signaling device 425 maylight up a green LED to indicate that the refrigeration system 105 isoperating within the desired parameters set by the user, or thesignaling device 425 may light up a red LED to indicate a problem withinthe refrigeration system 105. In other embodiments, the signaling device425 may be positioned on the controller 200 and configured to provide anindication of a problem within the refrigeration system 105. For examplethe signaling device 425 may be a buzzer or alarm integrated with thecontroller 200 and configured to provide an audible signal indicating aproblem within the refrigeration system 105.

The controller 200 also includes a communication interface 430. Thecommunication interface 430 may be configured to send and receive dataover a wired connection (e.g., Ethernet, thunderbolt, etc.) or awireless connection (e.g., Wi-Fi, Bluetooth, etc.). The communicationinterface 430 may also be configured to interface with the userinterface 420 such that the user interface 420 may send and receive datavia the communication interface 430 (e.g., to a mobile device).

The controller 200 also includes a temperature interface 453 and apressure interface 454. The temperature interface 453 is configured tobe communicably coupled to temperature sensors (e.g., inlet temperaturesensor 311 of FIG. 3) by a control line (e.g., control line 317 of FIG.3). The pressure interface 454 is configured to be communicably coupledto pressure sensors (e.g., inlet pressure sensor 312 of FIG. 3) by acontrol line (e.g., control line 327 of FIG. 3). The temperatureinterface 453 and the pressure interface 454 are each further configuredfacilitate communication between the sensors and the processing circuit400.

The controller 200 also includes a compressor interface 480 and anexpansion valve interface 490. The compressor interface 480 isconfigured to facilitate communication between the compressor assembly160 of FIG. 2 and the processing circuit 400 such that the processingcircuit 400 may selectively facilitate the operation of the compressorassembly 160. The expansion valve interface 490 is configured tofacilitate communication between the actuator sensor 325 of FIG. 3 andthe processing circuit 400 by control line 326 of FIG. 3. Additionallythe expansion valve interface 490 may be configured to facilitatecommunication between the actuator 125 of FIG. 3 and the processingcircuit 400 such that the processing circuit 400 may selectivelyfacilitate the operation of the actuator 125 by control line 397 of FIG.3.

The controller 200 is configured to execute the processes of FIGS. 6-7.The controller 200 is configured to determine if a component of therefrigeration system 105 (e.g., the actuator 125) has experienced anelectrical failure. For example, the controller 200 may communicate withthe inlet temperature sensor 311, outlet temperature sensor 321, ambienttemperature sensor 361, inlet pressure sensor 312, outlet pressuresensor 322, and ambient pressure sensor 362 by the respective controllines (e.g., control line 317, control line 327, and control line 367)to receive the temperature and pressure of the refrigerant at the inletand the outlet of the evaporator assembly 150 and the ambienttemperature and pressure. The controller 200 may then determine, by theprocessor, the superheat of the refrigeration system 105. The controller200 may also determine a maximum superheat and a minimum superheat basedon the ambient temperature and the ambient pressure. The controller 200may then determine whether the superheat is within specified parameters(e.g., the maximum superheat and the minimum superheat). Upondetermining that the superheat is not within the specified parameters,the controller 200 may signal the actuator sensor 325 to begincollecting data about the actuator 125. In some embodiments, theactuator sensor 325 is configured to detect the displacement of theactuator 125 (i.e., the actuator sensor 325 is configured as an encodersuch that the controller 200 may determine if the actuator 125 ismoving). In other embodiments, the actuator sensor 325 is configured todetect the electrical properties of the actuator 125 (e.g., current,voltage, power). In these embodiments, the controller 200 may determineif the actuator 125 is moving based on the electrical propertiesdetected by the actuator sensor 325. For example, the controller 200 mayreceive from the actuator sensor 325, a high current spike indicatingthat the actuator 125 is moving. Alternatively, the controller 200 mayreceive, from the actuator sensor 325, a low current spike indicatingthat the actuator 125 is not moving. The controller may determine, basedon the actuator 125 not moving, that the actuator 125 has experienced afailure (e.g., an electrical failure, a mechanical failure, etc.).

Now referring to FIGS. 6 and 7, flowcharts of a method for detectingfailure of an expansion valve (e.g., expansion valve 121) and respondingto the failure are shown, according to exemplary embodiments. In anexemplary embodiment, the methods shown are performed by the controller200 and connected components shown in FIGS. 1-5. Referring specificallyto FIG. 6, a method 500 for detecting a valve failure is shown accordingto an exemplary embodiment.

At step 510, the inlet temperature, the outlet temperature, the ambienttemperature, the inlet pressure, the outlet pressure, and the ambientpressure are monitored. For example, the inlet temperature sensor 311can measure the inlet temperature and provide the measurements to thecontroller. In some embodiments only one of the temperature or thepressure is monitored at each of the inlet sensors, outlet sensors, andambient sensors. For example, step 510 may include receiving, by thecontroller 200, data from the inlet pressure sensor 312, the outletpressure sensor 322, and the ambient pressure sensor 362 and storing thedata in the memory device 410. It should be appreciated that othercombinations of measuring temperature and pressure are possible. Forexample, the inlet pressure, the outlet pressure, and the ambienttemperature may be measured.

At step 520, a superheat of the refrigeration system 105 is calculatedbased on the measured values at step 510. The superheat may becalculated using the type of refrigerant and only temperature data orpressure data stored in the memory device 410. Additionally, thesuperheat of the refrigeration system 105 may be determined based on atleast one of the inlet temperature or the inlet pressure, at least oneof the outlet temperature or the outlet pressure, and, in someembodiments, the type of refrigerant. For example, the processor 405retrieves a first temperature value from the memory device 410originally received by the controller 200 from the inlet temperaturesensor 311 at step 510. The processor 405 may then retrieve a secondtemperature value from the memory device 410 originally received by thecontroller 200 from the outlet temperature sensor 321 at step 510. Theprocessor 405 may then calculate the superheat of the refrigerationsystem 105 based on the first temperature value and the secondtemperature value. For example, the first temperature value may be 35°F. and the second temperature value may be 42° F. The processor 405calculates the superheat of the refrigeration system as 7° F., or thedifference between the second temperature value and the firsttemperature value. The processor 405 may store this value in the memorydevice 410. Alternatively, the processor 405 may determine the superheatby retrieving pressure values from the memory device 410 stored duringstep 510. The processor 405 may also retrieve a saturated temperaturepressure-temperature table stored in the memory device 410. Theprocessor 405 may determine the inlet temperature and the outlettemperature based on the table and the pressure values, and thesuperheat of the refrigeration system 105 thereafter. The processor 405complete the calculation of the superheat and update the value stored inthe memory device 410 at a predefined time interval (e.g., multipletimes a second, ever second, every minute, etc.).

At step 525, the maximum superheat and the minimum superheat arecalculated and defined by the controller 200. For example, the processor405 may retrieve the ambient temperature or ambient pressure from thememory device 410. In some embodiments, the maximum superheat and theminimum superheat are determined by comparing the ambient temperature orthe ambient pressure with tabulated values for a particular refrigerant.

Step 530 may include performing a feedback control process (e.g., a PIcontrol process, a PID control process) to generate control signals forthe actuator based on values of the superheat calculated at step 520.The feedback control process may be configured to generate controlsignals that drive the actual superheat value towards a setpoint. Thesetpoint is between the maximum and minimum values calculated at step525. Accordingly, when the system is well-controlled, the superheatvalue is at approximately the setpoint value and between the maximum andminimum values. For example, the controller 200 may generate a controlsignal for the expansion valve 121 allowing the pressure of therefrigerant at the evaporator assembly 150 inlet to further decreasebased on the superheat of the refrigeration system 105 being too low(i.e., below or near the minimum superheat value). Alternatively, thecontroller 200 may generate a control signal for the expansion valve 121to decrease the pressure drop based on the superheat of therefrigeration system 105 being too high (i.e., above or near the maximumsuperheat value.)

Step 540 may include determining, by the processor, that the superheatof the refrigeration system 105 is between the maximum superheat and theminimum superheat. If the superheat of the refrigeration system 105 isbetween the maximum superheat and the minimum superheat, the controllerwill continue to step 550. If the superheat of the refrigeration system105 is not between the maximum superheat and the minimum superheat, thecontroller 200 will continue to step 560 (i.e., this indicates adeviation from the controlled state and may correspond to afault/error).

At step 550 the actuator 125 is identified as operating correctly by thecontroller. The controller may indicate that the actuator 125 isoperating correctly to the user by the user interface 420 or thesignaling device 425

At step 560, the controller 200 will begin monitoring the actuator 125at step. For example, the controller may begin monitoring a currentsupplied to the actuator 125 measured by actuator sensor 325.

Step 570 includes determining, by the processor 405, if the currentsupplied to the actuator 125 is varying. In an exemplary embodiment, theactuator 125 may receive current when the actuator 125 is not moving(e.g., idling). For example, the actuator 125 may be configured as astepper motor. In this configuration, the actuator 125 will continuouslyor periodically draw power to maintain positional accuracy when idle.For example, a stepper motor may draw power with a current spike atapproximately 2 amps (2 A) at every period (e.g., 60 or more times asecond, 5 times a second, every second, every minute, etc.). When theactuator 125 begins to move, the actuator 125 draws power with a currentspike at approximately 5 A. While moving, the actuator 125 continues todraw power with the current spike at approximately 5 A (see FIG. 8).

If the controller 200 determines that the current is sufficientlyvarying (e.g., from 2 A to 5 A), the controller 200 continues to step580.

In the event of a failure (e.g., an electrical failure), the actuator125 may not draw the necessary power to begin moving. For example, theactuator 125 may continue to draw power with current spikes at 2 A ifthe actuator 125 has failed (see FIG. 9). If the controller 200determines that the current is not sufficiently varying (e.g., thecurrent spikes are not increasing from 2 A to 5 A) the controller 200continues to step 590.

At step 580, the controller 200 determines that the actuator 125 isoperating correctly. The controller may provide a signal by the userinterface 420 or the signaling device 425 that the actuator 125 isoperating correctly. The controller may return to step 510 or 530 tocheck for failures again.

At step 590, the controller 200 determines that the actuator 125 is notoperating correctly. The controller 200 may signal, by the userinterface 420 or the signaling device 425, that the expansion valveassembly 120 has experienced a failure. More specifically, the actuator125 of the expansion valve assembly 120 has experienced an electricalfailure. In other embodiments, the controller is configured to identifya valve failure based on a mathematical equation or lookup table. Thecontroller may continue to method 600, return to step 510 to recheck forfailures, or both.

Now referring to FIG. 7, a flowchart of a method 600 ofpost-failure-identification procedures is shown. In some embodiments,the method 600 may be performed as a continuation of method 500 by thecontroller 200 as shown. At step 610, the controller 200 signals to thedevices that failure mitigation controls are enabled. At step 620, thecontroller signals, by the signaling device 425, an indication of valvefailure. Step 620 may further include present data to the user thatrepresents the failure mode identified by the controller 200. At step630, the controller 200 prepares a shutdown signal for each of thesystem components. At step 640, the controller 200 sends a shutdownsignal to the compressor assembly 160. At step 650, the controller 200sends a shutdown signal to the fans (e.g., fan 115 and fan 155).

The controller 200 advantageously signals a valve failure and, in someembodiments, begins failure mitigation controls such that the compressorassembly 160 is not damage by a high superheat or a low superheat. Forexample, the compressor assembly 160 may be damaged by a low superheatif the refrigerant is received by the compressor assembly 160 in aliquid state (i.e., the refrigerant did not take on enough thermalenergy to remain a vapor). In this case, the liquid refrigerant maydamage the compressor assembly 160. Alternatively, the compressorassembly 160 may be damaged by a high superheat if the refrigerant istoo hot when it is received by the compressor assembly 160. In thiscase, the refrigerant may lead to the compressor assembly 160overheating.

In one embedment, the failure mitigation controls may alternatively beperformed by a user. For example the user may be notified, by thesignaling device 425, of a valve failure. The user may then shut downthe refrigeration system 105 including the compressor assembly 160, fan115, and fan 155.

Now referring to FIGS. 8 and 9, a graph of current vs time supplied tothe actuator 125 is shown, according to exemplary embodiments. Referringspecifically to FIG. 8, a graph 800 of current 801 (Amps) vs time 802(milliseconds) is shown. The graph shows a first region 810 in which thecurrent 801 spikes up to about 2 A and a second region 850 in which thecurrent 801 spikes up to about 5 A. The first region 810 is indicativeof the actuator 125 of FIG. 3 idling. The current 801 increase over thetime 802 (e.g., the transition from the first region 810 to the secondregion 850) indicates that the actuator 125 is beginning to move. Due tothe increase in the current 801 between the first region 810 and thesecond region 820, the controller 200 may determine that the expansionvalve assembly 120 is properly functioning.

Referring now to FIG. 9 a graph 900 of current 901 (Amps) vs time 902(milliseconds) is shown. The graph shows a region 910 where the current901 spikes to about 2 A. The current 901 maximum, constant at 2 A, isindicative of the actuator 125 idling over the entire duration of thegraph 900 (e.g., between the minimum and maximum values of time 902).Due to the constant spikes in the current 901, the controller 200 maydetermine that the expansion valve assembly 120 is not functioning.

As utilized herein, the terms “approximately,” “about,” “substantially,”and similar terms are intended to have a broad meaning in harmony withthe common and accepted usage by those of ordinary skill in the art towhich the subject matter of this disclosure pertains. It should beunderstood by those of skill in the art who review this disclosure thatthese terms are intended to allow a description of certain featuresdescribed and claimed without restricting the scope of these features tothe precise numerical ranges provided. Accordingly, these terms shouldbe interpreted as indicating that insubstantial or inconsequentialmodifications or alterations of the subject matter described and claimedare considered to be within the scope of the disclosure as recited inthe appended claims. It should be noted that the term “exemplary” andvariations thereof, as used herein to describe various embodiments, areintended to indicate that such embodiments are possible examples,representations, or illustrations of possible embodiments (and suchterms are not intended to connote that such embodiments are necessarilyextraordinary or superlative examples).

The term “or,” as used herein, is used in its inclusive sense (and notin its exclusive sense) so that when used to connect a list of elements,the term “or” means one, some, or all of the elements in the list.Conjunctive language such as the phrase “at least one of X, Y, and Z,”unless specifically stated otherwise, is understood to convey that anelement may be either X, Y, Z; X and Y; X and Z; Y and Z; or X, Y, and Z(i.e., any combination of X, Y, and Z). Thus, such conjunctive languageis not generally intended to imply that certain embodiments require atleast one of X, at least one of Y, and at least one of Z to each bepresent, unless otherwise indicated.

The construction and arrangement of the elements of the refrigerationsystem and valve diagnostic system as shown in the exemplary embodimentsare illustrative only. Although only a few embodiments have beendescribed in detail in this disclosure, many modifications are possible(e.g., variations in sizes, dimensions, structures, shapes andproportions of the various elements, values of parameters, mountingarrangements, use of materials, colors, orientations, etc.). Forexample, the position of elements may be reversed or otherwise variedand the nature or number of discrete elements or positions may bealtered or varied. Accordingly, all such modifications are intended tobe included within the scope of the present disclosure. The order orsequence of any process or method steps may be varied or re-sequencedaccording to alternative embodiments. Other substitutions,modifications, changes, and omissions may be made in the design,operating conditions and arrangement of the exemplary embodimentswithout departing from the scope of the present disclosure.

The hardware and data processing components (e.g., processing circuit400) used to implement the various processes, operations, illustrativelogics, logical blocks, modules and circuits described in connectionwith the embodiments disclosed herein may be implemented or performedwith a general purpose single- or multi-chip processor, a digital signalprocessor (DSP), an application specific integrated circuit (ASIC), afield programmable gate array (FPGA), or other programmable logicdevice, discrete gate or transistor logic, discrete hardware components,or any combination thereof designed to perform the functions describedherein. A general purpose processor may be a microprocessor, or, anyconventional processor, controller, microcontroller, or state machine. Aprocessor also may be implemented as a combination of computing devices,such as a combination of a DSP and a microprocessor, a plurality ofmicroprocessors, one or more microprocessors in conjunction with a DSPcore, or any other such configuration. In some embodiments, particularprocesses and methods may be performed by circuitry that is specific toa given function. The memory (e.g., memory, memory unit, storage device)may include one or more devices (e.g., RAM, ROM, Flash memory, hard diskstorage) for storing data and/or computer code for completing orfacilitating the various processes, layers and modules described in thepresent disclosure. The memory may be or include volatile memory ornon-volatile memory, and may include database components, object codecomponents, script components, or any other type of informationstructure for supporting the various activities and informationstructures described in the present disclosure. According to anexemplary embodiment, the memory is communicably connected to theprocessor via a processing circuit and includes computer code forexecuting (e.g., by the processing circuit or the processor) the one ormore processes described herein.

The present disclosure contemplates methods, systems and programproducts on any machine-readable media for accomplishing variousoperations. The embodiments of the present disclosure may be implementedusing existing computer processors, or by a special purpose computerprocessor for an appropriate system, incorporated for this or anotherpurpose, or by a hardwired system. Embodiments within the scope of thepresent disclosure include program products comprising machine-readablemedia for carrying or having machine-executable instructions or datastructures stored thereon. Such machine-readable media can be anyavailable media that can be accessed by a general purpose or specialpurpose computer or other machine with a processor. By way of example,such machine-readable media can comprise RAM, ROM, EPROM, EEPROM, orother optical disk storage, magnetic disk storage or other magneticstorage devices, or any other medium which can be used to carry or storedesired program code in the form of machine-executable instructions ordata structures and which can be accessed by a general purpose orspecial purpose computer or other machine with a processor. Combinationsof the above are also included within the scope of machine-readablemedia. Machine-executable instructions include, for example,instructions and data which cause a general purpose computer, specialpurpose computer, or special purpose processing machines to perform acertain function or group of functions.

Although the figures show a specific order of method steps, the order ofthe steps may differ from what is depicted. Also two or more steps maybe performed concurrently or with partial concurrence. Such variationwill depend on the software and hardware systems chosen and on designerchoice. All such variations are within the scope of the disclosure.Likewise, software implementations could be accomplished with standardprogramming techniques with rule based logic and other logic toaccomplish the various connection steps, processing steps, comparisonsteps and decision steps.

The background section is intended to provide a background or context tothe invention recited in the claims. The description in the backgroundsection may include concepts that could be pursued, but are notnecessarily ones that have been previously conceived or pursued.Therefore, unless otherwise indicated herein, what is described in thebackground section is not prior art to the description and claims and isnot admitted to be prior art by inclusion in the background section.

It is important to note that the construction and arrangement of thesystems and methods as shown in the various exemplary embodiments isillustrative only. Additionally, any element disclosed in one embodimentmay be incorporated or utilized with any other embodiment disclosedherein. For example, the methods of the exemplary embodiment describedin at least paragraph(s) [0039] may be incorporated with any of thecomponents of the refrigeration system of the exemplary embodimentdescribed in at least paragraph(s) [0018]. Although only one example ofan element from one embodiment that can be incorporated or utilized inanother embodiment has been described above, it should be appreciatedthat other elements of the various embodiments may be incorporated orutilized with any of the other embodiments disclosed herein.

What is claimed is:
 1. A method of detecting electrical failure in arefrigeration system, the method comprising: controlling an expansionvalve assembly of the refrigeration system to drive a superheat value ofthe refrigeration system to a setpoint that is within a normal operatingrange of the refrigeration system, the normal operating range between amaximum superheat and a minimum superheat; subsequent to controlling theexpansion valve assembly to drive the superheat value of therefrigeration system to the setpoint, determining a present superheat ofthe refrigeration system; in response to the determined presentsuperheat of the refrigeration system being outside of the normaloperating range, detecting an electrical property of the expansion valveassembly of the refrigeration system; determining that the expansionvalve assembly has experienced an electrical failure based on at leastthe detected electrical property of the expansion valve assembly; and inresponse to the determination that the expansion valve assembly hasexperienced the electrical failure, generating a first signal indicatingthat the expansion valve assembly has experienced the electricalfailure.
 2. The method of claim 1, wherein determining the presentsuperheat comprises: detecting, by at least one sensor of a plurality ofsensors, a coil inlet temperature of the refrigeration system;detecting, by at least one sensor of the plurality of sensors, a coilinlet pressure of the refrigeration system; detecting, by at least onesensor of the plurality of sensors, a coil outlet temperature of therefrigeration system; detecting, by at least one sensor of the pluralityof sensors, a coil outlet pressure of the refrigeration system; andcalculating, based on at least one of the coil inlet temperature, thecoil inlet pressure, the coil outlet temperature, or the coil outletpressure, the present superheat of the refrigeration system.
 3. Themethod of claim 1, further comprising determining the maximum superheatand the minimum superheat for the refrigeration system by: detecting anambient temperature; detecting an ambient pressure; and calculating themaximum superheat and the minimum superheat for the refrigeration systembased on at least one of the ambient temperature or the ambientpressure.
 4. The method of claim 1, wherein the electrical property isat least one of a voltage, a current, or a power of the expansion valveassembly.
 5. The method of claim 1, wherein determining that theexpansion valve assembly has experienced the electrical failurecomprises: determining a variance of the electrical property of theexpansion valve assembly; and determining, responsive to thedetermination that the electrical property is not varying, that theexpansion valve assembly has experienced the electrical failure.
 6. Themethod of claim 1, further comprising providing, responsive todetermining that the expansion valve assembly has experienced theelectrical failure, a second signal to a compressor of the refrigerationsystem that is configured to cause a modification in an operation of thecompressor to mitigate effects of the electrical failure.
 7. The methodof claim 6, wherein the second signal is configured to: cause shut downof the compressor, based on the superheat of the refrigeration systembeing below the minimum superheat, such that liquid damage to thecompressor is mitigated; and cause shut down of the compressor, based onthe superheat of the refrigeration system being above the maximumsuperheat, such that thermal damage to the compressor is mitigated. 8.The method of claim 1, wherein determining whether the expansion valveassembly has experienced the electrical failure comprises: determining avariance of the electrical property of the expansion valve assembly; anddetermining, responsive to the determination that the electricalproperty is varying, that the expansion valve assembly is operatingnormally.
 9. A system comprising: a housing defining a temperaturecontrolled space; a thermal exchange system, coupled to the housing,configured to selectively control a temperature of the temperaturecontrolled space, and comprising: an actuator; and a controllerconfigured to perform operations comprising: controlling an expansionvalve assembly of the thermal exchange system to drive a superheat valueof the thermal exchange system to a setpoint that is within a normaloperating range of the thermal exchange system, the normal operatingrange between a maximum superheat and a minimum superheat; subsequent tocontrolling the expansion valve assembly to drive the superheat value ofthe thermal exchange system to the setpoint, determining a presentsuperheat of the thermal exchange system; in response to the presentsuperheat of the thermal exchange system being outside of the normaloperating range, detecting an electrical property of the expansion valveassembly of the refrigeration system; determining that the expansionvalve assembly has experienced an electrical failure based on at leastthe electrical property of the expansion valve assembly; and in responseto the determination that the expansion valve assembly has experiencedthe electrical failure, generating a first signal indicating that theexpansion valve assembly has experienced the electrical failure.
 10. Thesystem of claim 9, wherein: the actuator is configured to actuate anexpansion valve assembly; and the actuator is configured as a steppermotor such that the expansion valve assembly of the thermal exchangesystem is selectively movable by the stepper motor to a plurality ofpositions.
 11. The system of claim 9, wherein the electrical property isat least one of a voltage, a current, or a power of the expansion valveassembly.
 12. The system of claim 9, wherein the system comprises aplurality of sensors coupled to the controller, the thermal exchangesystem further comprising: a refrigerant configured to facilitatethermal energy exchange; an evaporator configured to change atemperature of the refrigerant and couple to at least one of theplurality of sensors; and a compressor configured to increase a pressureof the refrigerant and fluidly couple to the evaporator and actuate theactuator such that the expansion valve changes a pressure of therefrigerant.
 13. The system of claim 12, wherein the controller isconfigured to perform operations comprising: detecting, through at leastone sensor of a plurality of sensors, a coil inlet temperature of therefrigerant; detecting, through at least one sensor of the plurality ofsensors, a coil inlet pressure of the refrigerant; detect, through atleast one sensor of the plurality of sensors, a coil outlet temperatureof the refrigerant; detecting, through at least one sensor of theplurality of sensors, a coil outlet pressure of the refrigerant; storingthe coil inlet temperature, the coil inlet pressure, the coil outlettemperature, and the coil outlet pressure in a memory device; andcalculating, based on at least one of the coil inlet temperature, thecoil inlet pressure, the coil outlet temperature, or the coil outletpressure, the present superheat of the refrigeration system.
 14. Thesystem of claim 12, wherein the controller is configured to performoperations comprising: detecting, through at least one sensor of theplurality of sensors, an ambient temperature; detecting, through atleast one sensor of the plurality of sensors, an ambient pressure; andcalculating the maximum superheat and the minimum superheat for therefrigeration system based on at least one of the ambient temperature orthe ambient pressure.
 15. The system of claim 12, wherein the thermalexchange system further comprises a compressor configured to increasethe pressure of the refrigerant, and the controller is furtherconfigured to perform operations comprising generating a second signalthat is configured to: cause shut down of the compressor, based on thesuperheat of the refrigeration system being below the minimum superheat,such that liquid damage to the compressor is mitigated; and cause shutdown of the compressor, based on the superheat of the refrigerationsystem being above the maximum superheat, such that thermal damage tothe compressor is mitigated.
 16. A controller for diagnosing arefrigeration system, the controller configured to: determine a maximumsuperheat and a minimum superheat for the refrigeration system, themaximum superheat and the minimum superheat defining a normal operatingrange; control an expansion valve assembly of the refrigeration systemto drive a superheat value of the refrigeration system to a setpointthat is within the normal operating range; subsequent to control of theexpansion valve assembly, determine a present superheat of therefrigeration system; detect, responsive to the present superheat of therefrigeration system being outside of the normal operating range, anelectrical property of an expansion valve assembly of the refrigerationsystem; determine that the expansion valve assembly has experienced anelectrical failure based on at least the electrical property of theexpansion valve assembly; and generate, responsive to a determinationthat the expansion valve assembly has experienced the electricalfailure, a first signal indicating that the expansion valve assembly hasexperienced the electrical failure.
 17. The controller of claim 16,wherein the controller is further configured to: detect a firsttemperature and a second temperature within the refrigeration system;detect a first pressure and a second pressure within the refrigerationsystem; detect an ambient temperature; detect an ambient pressure;determine the present superheat of the refrigeration system based on atleast one of the first temperature, the second temperature, the firstpressure, or the second pressure; and determine the maximum superheatand the minimum superheat based on at least one of the ambienttemperature or the ambient pressure.
 18. The controller of claim 16,wherein the controller is further configured to: generate, responsive tothe determination that the expansion valve assembly has experienced theelectrical failure, a second signal to a compressor of the refrigerationsystem, the second signal configured to cause a modification in anoperation of the compressor to mitigate effects of the electricalfailure.
 19. The controller of claim 18, wherein the second signal isfurther configured to: cause shut down of the compressor, based on thesuperheat of the refrigeration system being below the minimum superheat,such that liquid damage to the compressor is mitigated; and cause shutdown of the compressor, based on the superheat of the refrigerationsystem being above the maximum superheat, such that thermal damage tothe compressor is mitigated.
 20. The controller of claim 16, wherein theelectrical property is at least one of a voltage, a current, or a powerof the expansion valve assembly.
 21. A method of detecting electricalfailure in a refrigeration system, the method comprising: determining apresent superheat of the refrigeration system, where the refrigerationsystem comprises a normal operating range that is between a maximumsuperheat and a minimum superheat; in response to the determined presentsuperheat of the refrigeration system being outside of the normaloperating range, detecting an electrical property of an expansion valveassembly of the refrigeration system; determining that the expansionvalve assembly has experienced an electrical failure based on at leastthe electrical property of the expansion valve assembly; in response tothe determination that the expansion valve assembly has experienced theelectrical failure, generating a first signal indicating that theexpansion valve assembly has experienced the electrical failure; andproviding, responsive to determining that the expansion valve assemblyhas experienced the electrical failure, a second signal to a compressorof the refrigeration system that is configured to cause a modificationin an operation of the compressor to mitigate effects of the electricalfailure.
 22. The method of claim 21, wherein determining the presentsuperheat comprises: detecting, by at least one sensor of a plurality ofsensors, a coil inlet temperature of the refrigeration system;detecting, by at least one sensor of the plurality of sensors, a coilinlet pressure of the refrigeration system; detecting, by at least onesensor of the plurality of sensors, a coil outlet temperature of therefrigeration system; detecting, by at least one sensor of the pluralityof sensors, a coil outlet pressure of the refrigeration system; andcalculating, based on at least one of the coil inlet temperature, thecoil inlet pressure, the coil outlet temperature, or the coil outletpressure, the present superheat of the refrigeration system.
 23. Themethod of claim 21, further comprising determining the maximum superheatand the minimum superheat for the refrigeration system by: detecting anambient temperature; detecting an ambient pressure; and calculating themaximum superheat and the minimum superheat for the refrigeration systembased on at least one of the ambient temperature or the ambientpressure.
 24. The method of claim 21, wherein the electrical property isat least one of a voltage, a current, or a power of the expansion valveassembly.
 25. The method of claim 21, wherein determining that theexpansion valve assembly has experienced the electrical failurecomprises: determining a variance of the electrical property of theexpansion valve assembly; and determining, responsive to thedetermination that the electrical property is not varying, that theexpansion valve assembly has experienced the electrical failure.
 26. Themethod of claim 21, wherein determining whether the expansion valveassembly has experienced the electrical failure comprises: determining avariance of the electrical property of the expansion valve assembly; anddetermining, responsive to the determination that the electricalproperty is varying, that the expansion valve assembly is operatingnormally.
 27. A system comprising: a housing defining a temperaturecontrolled space; a thermal exchange system coupled to the housing andconfigured to selectively control a temperature of the temperaturecontrolled space, the thermal exchange system comprising: an actuatorcoupled to an expansion valve; a plurality of sensors; a refrigerantconfigured to facilitate thermal energy exchange; an evaporatorconfigured to change a temperature of the refrigerant and couple to atleast one of the plurality of sensors; a compressor configured toincrease a pressure of the refrigerant and fluidly coupled to theevaporator to actuate the actuator such that the expansion valve changesa pressure of the refrigerant; and a controller coupled to the pluralityof sensors and configured to perform operations comprising: determininga present superheat of the refrigeration system, where the refrigerationsystem comprises a normal operating range that is between a maximumsuperheat and a minimum superheat; in response to the present superheatof the refrigeration system being outside of the normal operating range,detecting an electrical property of an expansion valve assembly of therefrigeration system; determining that the expansion valve assembly hasexperienced an electrical failure based on at least the electricalproperty of the expansion valve assembly; in response to thedetermination that the expansion valve assembly has experienced theelectrical failure, generating a first signal indicating that theexpansion valve assembly has experienced the electrical failure; andgenerating a second signal that is configured to: cause shut down of thecompressor, based on the superheat of the refrigeration system beingbelow the minimum superheat, such that liquid damage to the compressoris mitigated; and cause shut down of the compressor, and based on thesuperheat of the refrigeration system being above the maximum superheat,such that thermal damage to the compressor is mitigated.